This invention relates to a vertical venetian blind of the type in which the slats are supported on a carriage for movement along the trackway to enable opening and closing of the blind and in which the slats are also supported on the carriage for rotation about the lengthwise axis of the slat, to control light that passes through the blind, an example of which is shown in U.S. Patent to Eldridge, Jr. et al, No. 3,280,891. In the vertical venetian blind construction disclosed in that patent, the carriages are moved along a channel shaped trackway by means of traverse cords having relatively parallel runs extending lengthwise of the trackway and connected to a lead or master carriage, and with links interconnecting adjacent carriages to control spacing between the carriages. The slats on the several carriages are simultaneously rotated by a spline shaft that extends longitudinally of the track and the carriages each have rack and pinion gearing that meshes with the spline shaft and which rotates slot carriers connected to each of the slats. The spline shaft is driven by a cord and pulley type drive through a speed reducer located on the end of the spline shaft.
Such vertical venetian blind apparatus require a relative large number of carriages for each installation, with each carrier having a slat carrier, gears for rotating the slat carrier from the spline shaft, and carriage spacer links to control spacing between the carriages. The prior venetian blind construction was such that it was relatively expensive to manufacture and assemble the various parts that made up each carriage including the gearing and spacer links. Moreover, the traverse cords for moving the carriages along the channel are located within the channel and, in the prior constructions, it was a tedious and time-consuming operation to connect the traverse cord runs to the lead or master carriages. Further, in the prior vertical venetian blind constructions, the drive mechanism for rotating the spline shaft was located at the end of the channel and necessitated substantial space between the end slat and the window opening in order to operate the blind so that there was a light passage between the end slat and the window opening.